Metal arc welding of 90-10 type copper-nickel material



Unite States Patent IVIETAL ARC WELDING OF 90-10 TYPE COPPER-NICKELMATERIAL George Raymond Pease, Westfield, and Theodore Ephraim Kihlgren,Berkeley Heights, N. 3., assignors to The International Nickel Company,Inc., New York, N. Y., a corporation of Delaware No Drawing. Originalapplication November 6, 1953, Serial No. 390,732, new Patent No.2,745,771, dated May 15, 1956. Divided and this application November 3,1955, Serial No. 544,822

Claims. (Cl. 29-194) The present invention relates to the arc welding ofmetal and, especially, to a flux-coated electrode and an arcweldingmethod for producing sound, strong and ductile weld deposits and, moreparticularly, to a flux-coated copper-nickel arc-welding electrodeadapted for producing substantially pore-free, sound, strong and ductileweld deposits on iron-bearing copper-nickel material and also to theresultant weld deposit and welded product.

Copper-nickel alloy of the 90(copper)-10(nickel) type containing about5-15 nickel and approximately 11.5% iron is a relatively new material.The prior art relative to joining this material is therefore verylimited. While attempts have been made to weld this material using a 70%copper-30% nickel alloy, no electrode having a core wire ofsubstantially matched composition has been available for satisfactorilywelding the aforementioned iron-bearing 90-10 type copper-nickel alloy.The recent critical shortage of nickel served to focus attention on thisnew alloy as a substitute for 70/30 copper-nickel in the shipbuildingindustry. This prompted efforts to produce a flux-coated electrodehaving a core wire of a composition similar to or matching that of theiron-bearing 90-10 type copper-nickel material to'be poined. However,prior to applicants invention it has not been possible to apply knownfluxes to such a core wire and to consistently produce satisfactorywelds. The are has been inclined to be bubbly and the slag removalsomewhat diflicult. Extreme care has been required to avoid undercuttingin a deep V. Excessive porosity also has been encountered. Furthermore,such welds have not possessed strength properties of the desiredmagnitude. Although many attempts were made to overcome the foregoingdiificulties and other difliculties, none, as far as we are aware, wasentirely successful when carried into practice commercially on anindustrial scale.

It has now been discovered that by the use of applicants novelcombination of a particular fiux coating with an appropriately alloyed9010 type coppernickel core wire, welds are readily obtained in anarc-welding process that are virtually porosity-free and that haveattractive strength properties and good ductility.

It is an object of the invention to provide a 90-10 type.

cupro-nickel weld deposit which is sound, strong and ductile andsubstantially free from porosity.

The invention further contemplates providing an article of manufacturehaving a welded joint in 90-10 type cupronickel material with the weldmetal also of a 90-10 type cupro-nickel composition, the weld beingsound, strong and ductile and substanially free from porosity.

It is a further object of the invention to provide a 90-10 typecopper-nickel welded joint substantially devoid of hot cracking.

It is another object of the invention to provide a 90-10 typecopper-nickel weld deposit substantially devoid of hot cracking.

It is also an object of the invention to provide a 90-10 typecopper-nickel welded joint, the weld being sound,

' the core wire.

strong and ductile, substantially free from substantially devoid of hotcracking.

Other objects and advantages of the invention will become apparent fromthe following description.

Generally speaking, the present invention contemplates a novel electrodecomprising a particular flux coating on a copper-nickel alloy core wireespecially adapted for the electric-arc welding of copper-nickel alloys.According to the present invention, there is a delicate balance of theconstituents of the flux coating in relation to the core wire to producean arc-welding electrode having good are behavior and slagcharacteristics producing a good weld contour and a high qualitydeposit. The electrode provided by the present invention isintended foruse particularly with direct current. This electrode depositsradiographically-sound metal and is readily operable in flat andvertical positions and can be used in the overhead position inappropriate diameters.

The flux coating of the electrode provided by the present porosity andinvention is given in Table 1.

TABLE 1 Flux composition Parts by Weight Ingredients Broad PreferredPreferred Range Range Example Dry Flux:

Calcium Carbonate 6 to 26 10 to 20 16 Calcium Fluoride 15 to 30 22 to 3025 Cryolite 15 to 30 20 to 25 24 Titania 20 to 30 22 to 28 24Manganese 1. 7 to 8. 5 1.7 to 4. 3 2. 6 Silicon up to 1. 3 CalciumSilicate 2 to 10 4 to 8 5 Bentonite 2 to 5 2 to 4 3 1 Calcium silicatemay be used in any appropriate form, such as Wollastonite. An equalquantity of anhydrous sodium silicate may be substituted for the calciumsilicate if desired, with some attendant loss 01' extrudability.

The binder to be used in the flux composition is to be of a suitablewater dispersible type. For example, a satisfactory binder can have thefollowing composition:

1 (For both broad and preferred ranges of flux.)

In preparing the flux coating from the foregoing dry ingredients andbinder, the binder is added to the mixture of dry ingredients, togetherwith additional water as needed, to obtain a consistency suitable forextrusion with Although it is preferred to use Mordex as the invertsugar solution in the binder, other types of invert sugar solutions maybe used. Furthermore, sodium silicate solutions and invert sugarsolutions of different specific gravity from those specified in theforegoing binder also may be used. A solution containing an equivalentamount of potassium silicate may be substituted for the sodium silicatesolution in the binder.

The manganese and the silicon may be incorporated in p Calciumcarbonate, calcium silicate, calcium fluoride, cryolite and titania inthe flux are all nominal slagforming agents. The calcium carbonate andtitania are also arc stabilizers; The are can be expected to losestability materially if the flux contains less than the minimum amountsof calcium carbonate and titania set forth in Table I. When the cryoliteis used inamounts less than about 15% in combination with the otheringredients of the flux in the rangesset forth in Table 1, the weldquality and. all-position operability are adversely affected. Calciumsilicate in combination with the other ingredients in the fiux providesan additional increment of arc stability and likewise provides a markedimprovement in electrode .operability in the vertical position,which.im-. provement is not evident without the presence of the calciumsilicate. Nickel-50 silicon may be included in the coating up to 2.5%,as an addedfiptional source of silicon, to improve the strengthproperties of the: weld without damaging arc characteristics. willprogressively detract from operability. Manganese when included with theother ingredients in the flux enhances arcing characteristics. In theabsence of bentonite, extrudability of the flux would be reduced,thereby adversely affecting the manufacture of the coated weld rod.

Applicants special core wire for the electrode of the present inventionis a copper-base alloy containing, as the essential ingredients, copper,nickel, iron, manganese and silicon. The aforementioned, essentialingredients are co-presentin'the' core wirein controlled and criticalamounts. The broad and preferred ranges of the ingredients of the corewire of the present invention together with a preferred example thereofare given in Table 2. The broad range, the preferred range and thepreferred example of the core wire are used withthe broad range, thepreferred range and the preferred example, respectively, of the fiuxcomposition of Table 1.

TABLE 2 Core wire composition Percent by- Weight Elements BroadPreferred Preferred Range Range Example Nickel 5 to 15 9 to 11 10 on0.5to2 11:01.6 1.5 Manganese 0.05 to 1 0.15 to 0.5 0. 4 'con. 0.2 to 10. 2 to 0.5 0. 4 Magnesium 08 max. 0. max.

The balance of the core wire composition in Table 2 s pp n ll m unts ofer elem n snoted absent or kept low. The total amount of any othermetals- (zinc, cobalt, etc.) should be not more than about 0.50%;

A minimumof about 0.2% silicon in the. core: wire seems. to eliminatemost of the weld porosity and has a strengthening effect .on the weldmetal and also improves the soundness of the weld ascompared with anelectrode havingsilicon in the coating only. About 0.4% silicon in thecore wire appears to be optimum. Furthermore,

the silicon in the core wire eliminates porosity without;

impairing electrode operability.

Higher amounts welds. As a result of tests, applicants have establishedthat if the 0.05% maximum lead contamination level that is nowrecognized in base metal specifications must, for manufacturing reasons,be carried into filler metal specifications, not more than about 0.15%silicon can safely be present in the 90-10 type copper-nickel weldmetal. If the lead contamination in the weld metal can be held to 0.02%maximum, the permissible silicon content in the weld metal can bedoubled with modest -im-- Maximum percent Pb in weld=0.08

0.2 percent Si in weld Magnesium, although not normally necessary,should. be added-where melting conditions and production of the corewire point to a possibility of sulfur contamination. Magnesium incombination with the aforementioned essen tial ingredients also improveshot malleability and hot working operations. The magnesium may beincluded for the aforementioned purposes in small amounts upsto about0.08%, preferably in small amounts up tozabout The alloy can beprepared, and the core wire canbe made therefrom, by any conventionalalloying and manu-. facturing procedures such as are well known in theart.

I The flux coating can likewise be made, and the core Ithasbeenfoundthat lead and silicon act synergistia cally to produce hotcracking in 9040 type copper-nickel wire coated therewith, by anyconventional manufacturing procedures such asare well known in the art.However,

on completion of the low temperature drying treatment.

of thecoated core wire, a bake at about 550 F. for about two hours isapplied.

The combinations of core wire diameters and electrode outside diametersset forth in Table. 3 have been found For the purpose of giving-thoseskilled in the art abetter understanding of the invention and a betterappreciation-of the advantages of the invention, the followingillustrative data are given:

I.- -RES.ISTANCE TO WELD HOT CRACKING Metal deposited by the preferredelectrode example (the preferred example of the core wire together. withthe preferred example of the flux coating thereon as set forth in Tables1 and 2) has satisfactorily passed .the-

X-weld crack'test. In making this test, two 3-inch long pieces cut from1-inch square bar. stock are clamped with theiredges together to form adouble-V groove or X'-- joint. Then passes are-laidin, two at a time,on.- alters nate sides of the joint, allowing the specimen to. cool toabout F. between passes. The specimen is clamped for the early part ofthe test and is subsequently left unclamped for the balance of the test.During welding;v

each pass is. examined visually and on completiontof welding, two crosssections about /8 inchtop /4 inch from;

each end are polished and etched and examined for cracks; A,completedescription of the test, and illustrations of the testspecimen',.mayybe foundin .the..Welding Journal, vol. 24, 769-8 to 775-S(November 1946). A silicon content in the Weld of the order of 0.1% to0.15% contributes materially. to the weld strength, insures freedom fromweld unsoundness and at the same time is well below the threshold limitof about 0.35% to 0.4% silicon at which hot cracking will occur evenwith low lead and sulfur levels. Any increase in the amount of either orbotlrlead and sulfur tends to diminish the hot cracking resistance atall silicon levels. For instance, a deposit made by using an electrodeof the preferred example but containing about 0.12% lead and 0.05%silicon was severely cracked in the X-weld crack test. The hazardassociated with the presence of lead, particularly, increases as thesilicon content of the weld plate. These transverse :bend test specimenswere bent in a jig to a U shape with the weld face in tension. Uponremoval from the jig the convex surface was examined for the appearanceof cracks or other open defects. The results of this test are reportedin the column headed 180 guided U-bend test. After completion of theguided bend test the bend specimens were then flattened to failure asfree ben-d specimens and elongation was measured acros the weld. Acomplete description of these bend tests and illustrations of the testspecimens may be found in the American Welding Society publicationWelding Handbook, 3rd edition, 1950, pages 1450 to 1459, inclusive. Theresults of the foregoing tests are given in Table 4.

TABLE 4 Transverse bend test [Butt joint, 95" plate] TATIVE WELDS Buttwelds were made on /8" iron-bearing 90-10 type copper-nickel plate ofthe same composition as the bar stock used in the aforementioned weldhot cracking tests and using the preferred electrode example (apreferred example of the core wire together with the preferred exampleof the flux coating thereon as set forth in Tables 1 and 2) butcontaining different amounts of silicon in the core wire as set forth inTable 4. Transverse tensile test specimens were cut from the butt jointsin the Welded plate. These specimens were tested to determine thetensile strength and the yield strength of the Si Siiu Free Weld WeldNo. Weld Content Weld, 180 Guided bend test Hardness Position of Core,percent U-bend test (percent (Rock. B) percent elong.)

Satisfactory 56 i 0.43 0. 09s 62 39-50 approachesthe aforementionedlimit of about 03 5% to Transverse tensile test 0.4%. It 18 thereforepreferred, generally speaking, to use a combination of coating and corewire within the 35 [Buttj i t %"p1at 1 preferred ranges of Tables 1 and2 which will insure weld metal silicon contents of the order of 0.1% to0.15%. Yield Strength, Under conditions of severe restraint, such as inthe X- Weld Tensile weld crack test, the threshold limit for lead withsilicon Weld No. Position Strength, in the desired range is determinedby the relationship 40 (lgzet expressed in the equation load Maximumpercent Pb in Weld:

Fl 2, 29, w -m s m l i.. 232 5g gggg er lea Sulfur may be of the orderof 0.02% to 0.05%. How- 4- 21,900 23,900 45,100 ever, the permissiblesulfur content is dependent upon the magnesium content of the weld andis preferably held to 0.02% maximum. High magnesium contents in the weldmetal will permit more sulfur to be present than low magnesium contents,but magnesium recoveries are Representative l weld metal analyses verypoor in metal are welds.

The bar stock used in making the aforementioned weld [it" Electrode] hotcracking tests had the following approximate com- P W h ercent by eig tposmon' Elements Percent Copper 88 Wire N 0. A Weld Metal Wire No. BWeld Metal Nickel 10.1 10 07 10 04 1o 27 10 4 1111 14 1.5'3LIIIIIi.1'3.:::t:: 1.54.1113: in: Manganese 0.4 511M011 meta- B'eifi jjtelnetelem...

II.PROPERTIES AND COMPOSITION OF REPRESEN- 1 Including small amounts ofother incidental elements and impurities which may be present incommercial practice as mentioned in regard to Tables 2 and 5.

III.COMPOSITION OF WELD DEPOSIT tion in the composition of thecopper-base weldmetal deposit can be expected, allowing for theaforementioned variables The balance of the weld metal composition ofTable is copper, except for small'amounts of other incidental elementswhich may be present-in the balance-with-the copper in commercialpractice due to their presence in the electrode, i. e., in the core wireand/0r inthe flux coating, as mentioned herein. The aforementionedcopper content ofthe weld metal composition-isabout 79.5% to 94% in thebroad range and about 84.5% to 89.4% in the preferred range.

IV.EFFECT OF SILICON IN THE WELD "Butt-joints were preparedin/s-inchthick iron-bearing 90-10 type copper-nickel platetof the samecomposition as the stock material used in the foregoing weld-cracktests) using electrodes so formulated as to provide the indicated weldmetal silicon contents. Transverse tensile test and bend test specimenswere cut from the butt joints in the welded plate. These specimens weretested to determine the tensile strength and the elongation in bend ofthe welded material in accordance with the procedure outlined in sectionII. X-raytests were also-made to determine the weld quality. The resultsof the foregoing tests are given in Table 6.

TABLE 6 I Tensile Percent Weld Quality Percent Silicon in Weld Strength,Elongation (X-Ray) p. s. i. in Bend 42, 100 50 scattered porosity. 43,300 56 n. 5. very slight porosity.

1 N. f.=no failure.

It is to be observed in this table that'as the weld metal siliconcontent increases the strength properties are materially increased andweld porosity is materially decreased.

V.DUCTILITY on Rial-HEATED METAL ARC WELns An additional series of testsserves to indicate that there I is good ductility in the welds evenafter deliberate exposure of welded joints to temperatures withintheir-on precipitation range and up to 1650 F. In this series of tests,the results of which are shown in Table 7, a number of A inch'wide'transverse face bend specimens were prepared from a single weldjoint made in %-inch 90-l0 type copper-nickel plate (of the samecomposition as the plate material used in the foregoing section I)with a-inch 'electrode'having' flux and core wire -compositions within thebroad ranges of Tables 1 and 2, the core wire having 1.7% iron. The freebend tests were made in accordance with the procedure outlinedinsection'II. Weld elongation was measured on each specimen afterexposure, in air, to the indicated test temperatures.

The present invention is of wide application for producing substantiallypore-free weld deposits on iron-bearing 90-10 type cupro-nickel alloymaterial, especially where it is desired to obtain a weld depositsubstantially matching the material welded in composition. The presentinvention is particularly applicable to the shipbuilding industry, forexample, for the construction of condensers and piping and for use inother fields where resistance is required to the destructive action ofsea water, in particular to the action of rapidly moving sea water.

The present application is a division of applicants copending priorapplication Serial No. 390,732 filed Novemher 6, 1953, now Patent No.2,745,771 granted May 15, 1956.

Although the present invention has been described in conjunction withpreferred embodiments, it is to be understood-that modifications andvariations may be resorted to without departing from the spirit andscope of the invention, as those skilled in the art will readilyunderstand. Such modifications and variations are considered to bewithin the purview and scope of the invention and appended claims.

We claim:

-1. As an article of manufacture, a welded structure comprising at-leasttwo members made of a 90-l0'type copper-nickel alloy containing 5% to15% nickel, 1% to 1.5% iron'and the balance substantially copper joinedtogether by atleast one weld metal deposit composed of an alloy havingas the essential elements 84.5% to 89.4%

copper, 9% to 11% nickel, 1% to 2.2% iron, 0.5% to 1.25% manganese, and0.1% to 0.15% silicon with any lead contamination in the resultant weldmetal not exceeding the amount being expressed by the equation:

Maximum percent lead in weld=0.08

0.2 X percent silicon in weld 2.As an article of manufacture, a weldedstructure comprising at'le'ast two members made'of a 90-10 typecopper-nickel alloy containing 5% to 15% nickel, 1% to 1.5% iron and thebalance substantially copper joined together by at least one weld metaldeposit composed "of an alloy having as the essential elements 79.5% to94% copper, 5% to 15% nickel, 0.5% to 2.5%iron, 0.4% to 1.75% manganese,and 0.03% to 0.4% silicon with anylead contamination in the resultantweld metal not exceedingthe amount expressed by the equation: I

0.5% to 1.25% manganese, and 0.1% to 0.15% silicon.

4. As an article of manufacture, a wcldedst'ru'cture comprising at leasttwo members made of a -'l0'type coppernickel alloy containing 5% to 15%nickel, 1% to 1.5 iron and the balance substantially copp'er'joinedtogether by at least one weld metal deposit composed of an alloyhavingas the essential elements 5% to 15% nickel; 0.5% to 2.5%i'ron, 0.4% to1.75% manganese, and'0.03 to 0.4% silicon, and the" balance essentially9 copper, the copper content being between 79.5% and about 0.03% to 0.4%silicon and the balance essentially 94%. copper.

5. As an article of manufacture, a welded structure comprising a membermade of a 90-10 type copper-nickel Refel'emes Cited in the file of thisPatent alloy containing 5% to 15% nickel, 1% to 1.5% iron and 5 UNITEDSTATES PATENTS the balance substantially copper, and having a Wei-ddeposit consisting essentially of 5% to 15% nickel, 0.5% to 2.5% iron,about 0.4% to 1.75% manganese, and

1,906,567 Fritshle May 2, 1933 2,117,106 Silliman May 10, 1938

1. AS AN ARTICLE OF MANUFACTURE, A WELDED STRUCTURE COMPRISING AT LEASTTWO MEMBERS MADE OF A 90-10 TYPE COPPER-NICKEL ALLOY CONTAINING 5% TO15% NICKEL, 1% TO 1.5% IRON AND THE BALANCE SUBSTANTIALLY COPPER JOINEDTOGETHER BY AT LEAST ONE WELD METAL DEPOSIT COMPOSED OF AN ALLOY HAVINGAS THE ESSENTIAL ELEMENTS 84.5% TO 89.4% COPPER, 9% TO 11% NICKEL, 1% TO2.2% IRON, 0.5% TO 1.25% MANGANESE, AND 0.1% TO 0.15% SILICON WITH ANYLEAD CONTAMINATION IN THE RESULTANT WELD METAL NOT EXCEEDING THE AMOUNTBEING EXPRESSED BY THE EQUATION: MAXIMUM PERCENT LEAD IN WELD=0.080.2 XPERCENT SILICON IN WELD